Technical Field
The present invention relates to compositions suitable for topical administration, the compositions comprising pharmacologically active polypeptides that are encapsulated in a liposome and/or nano-liposome. The invention also relates to methods of manufacturing the liposome and/or nano-liposome formulations. The invention further relates to methods for improving and/or treating skin conditions, enhancing wound healing, and for inhibiting subcutaneous fat formation.
Related Art
Heat Shock Protein 90a, abbreviated as HSP90a hereafter, is a dimer composed of two monomers containing phosphate groups, and having a molecular weight of 90 KD. The two monomers tend to become easily oligomerized under some conditions, e.g., when present in aqueous solution. Most Heat Shock Proteins have been known to function intracellularly. Other reports indicate that some Heat Shock Proteins work outside the cell, suggesting alternative physiological roles. The role of HSP90a in immune-regulation has been suggested10, 12. However, no systemic studies have been carried out with HSP90a, nor has it been described as having any activity for affecting skin conditions, such as atopic dermatitis or skin aging, or as affecting subcutaneous fat formation or accumulation. The relatively large size of the HSP90a fragment has precluded the use of this molecule in topical preparations, as it is unable to penetrate to the skin dermis layer6.
Atopic dermatitis (AD) is a chronic dermal disorder caused by defects in stratum corneum, which is generally considered idiopathic9. It affects children and adults as well. Its epidemiology has been known to associate with hereditary4 or environmental causes7, and immunological factors9.
There is no known cure for AD thus far, although treatments may reduce the severity and frequency of flares. Commonly used compositions for treating atopic dermatitis include small molecule based compounds with properties of anti-histamine, steroids or immune suppression. Alternatively systemic immune suppressing agents may be tried such as cyclosporine, methotrexate, interferon gamma-1b, mycophenolate mofetil and azathioprine4. However since these small-molecules based compounds accompany such serious adverse effects as deterioration of immune function upon long term use, new materials to overcome such barriers are needed in the treatment of these and other conditions.
Unlike small molecule based medicine, there are significant advantages in using a polypeptide as active ingredients for the treatment of dermal disorders and/or preparing skin cosmetic products. For example, polypeptides are generally more compatible with interactions with the immune system and cells, and generally decomposed in a pro-physiological manner within the body, hence generating fewer side effects compared to small molecule (chemical) containing preparations, especially during long term use. Furthermore, as relates to uses in cosmeceutical preparations, small molecule containing cosmetic products generally produce only short term cosmetic effects, while polypeptide containing cosmeceutical preparations have been described as providing longer term improvement of overall skin condition, and even skin rejuvenation3. However, the overall size and bulkiness of many potentially useful polypeptides prevents the penetration of these ingredients into skin tissues.
Traditionally, macromolecules having a molecular weight of 500 Daltons or more are considered too large to pass through the skin epidermis due to the skin keratin barrier6. Even when used with chemical penetration enhancers, macromolecules having a molecular weight of more than 2000 Daltons are considered practically implausible for topical use, as they are unable to penetrate the skin epidermis. Therefore, peptides developed as pharmaceutical/cosmetic ingredients have been limited to those having a much smaller size, such as a size of less than 10 amino acids (roughly about 1100 Daltons MW), so as to optimize the delivery of the active ingredient to the skin dermis. Thus, many potentially useful polypeptides having a size of 10 amino acids or greater have not been utilized in topical preparations. Delivery of an active ingredient, such as a polypeptide, to the skin dermis layer, is necessary to provide the most pharmaceutically meaningful outcomes with functional pharmaceutical/cosmetic preparations.
Liposome based delivery of human growth hormone (hGH), having a MW of 22,124 Daltons (191 amino acid size), has been reported1-3. However, challenges associated with effective topical delivery of other pharmacologically different peptides/proteins, such as heat shock protein Hsp90a, remain.
A 115 amino acid fragment of Heat Shock Protein, termed HPf, is encoded by an amino acid sequence spanning between the linker and the middle domain of the native endogenous HSP sequence (FIG. 1). This fragment has been reported to ameliorate skin necrosis caused by diabetic ulcer.8 Improvements in delivery products are, however, lacking for facilitating fuller use and formulation of these and related polypeptides.
Subcutaneous fat is the layer of subcutaneous tissue that is most widely distributed and is mainly composed of adipocytes. The number of adipocytes varies among different areas of the body, while their size varies according to the body's nutritional state (Subcutaneous Tissue. Medical Subject Headings (MeSH). NLM Retrieved 5 Jun. 2013). Some reports suggest that reducing the size of fat cells could improve fat cell sensitivity to insulin5. Numerous small molecule based oral delivery medicines have been developed and marketed for suppressing the accumulation of fat. Oral administration of these types of preparations, however, is associated with adverse side effects. A topical preparation would be more effective in such applications, and would offer the advantage of targeting problem fat deposit areas on the body, among other advantages.
One of the many barriers in the use of polypeptides in topical preparations remains the size and bulkiness of these polypeptide and protein molecules, which, because of the structure of skin tissues, do not penetrate the skin sufficiently to provide beneficial pharmacological and physiological effects in the body. Conventional approaches to this problem have been the use of mesotherapeutic devices, such as micro needles, electroporation devices, laser treatments, and infrared irradiation. For a variety of reasons, these approaches have not provided a sufficiently effective and convenient approach for topical administration of peptide-containing preparations. Problems associated with sufficient shelf-life and product biological stability also limit the use of polypeptide/peptide/protein based topical and other preparations.
A need continues to exist in the medical arts for improved topical preparations with preserved bioactivity and enhanced shelf-life of identified polypeptide/protein-based molecules. In addition, a need continues to exist for achieving effective delivery of these and other potent polypeptide/protein agents deep into skin tissues to achieve maximal physiological benefit to the patient. The present invention provides a solution to these and other technical problems in the medical arts for the use of polypeptide and/or protein-based molecules in topical and other delivery formulation applications and treatment methods.